The WP systems sends a lot of mails to authors. There also plugins who use email notifications for authors.

But, let say I have a user, who is managed by two persons (because it's a company, an entity that is more then one person) - I want all the emails to be sent also to a second Email address, that I will enter in the profile page of that WP user.

What is the best way to achieve this? I know how to add a field to the profile page, but I don't know how to send every notification that the user gets to the second email address.
please help :)

If you have a lousy host it's probably time to move hosts, not route around their lousiness ;-). This is certainly easier than a code based solution (for non technical users).
– RefinerFeb 27 '12 at 22:36

Yes, I know. but just for the challange. what would you do. in the end i've changed hosting and forward the Email as you suggested, and as I also thought would be the best solution. But what if?
– Asaf ChertkoffMar 2 '12 at 10:56

A suggestion, albeit a sorta hack, I'd like to make is to use a mailing list. You can add an infinite number of emails to a mailing list.

An alternative you could do is to use the publish_{$posttype} hook to send email notificiations through wp_mail. The wp_mail function's $to parameter takes either a string or an array so you could pass in multiple email addresses.

I attempted a sample code block (above). A suggestion if you plan on using this on a production site, use a cron job if you have a lot of registered users, otherwise I'm pretty sure this will cause a timeout in PHP.